using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading;
using System.Threading.Tasks;
using franz;
using Ical.Net;
using Ical.Net.CalendarComponents;
using Ical.Net.DataTypes;
using Ical.Net.Serialization;
using Newtonsoft.Json;
using ShowHandlers;

namespace director
{
    class Program
    {
        //private static Telefranz tf;
        public static Config conf;
        private static TimeSpan calendarNaptime = TimeSpan.FromHours(1);
        private static Scratch scratch;
        private static HttpClient httpClient;
        private static DateTime searchStart = DateTime.Now; //is it slower to just call datetime.now every time? /shrug
        private static DateTime searchEnd = DateTime.Now.AddDays(7);
        //I don't understand why the entire .net ecosystem insists on ignoring ToString(). Is it really that much fun writing a serializer factory? ...java programmers.
        private static EventSerializer ser = new EventSerializer();
        private static readonly ConcurrentQueue<Schedulable.Schedulable> workQueue = new ConcurrentQueue<Schedulable.Schedulable>();
        private static readonly AutoResetEvent _signal = new AutoResetEvent(false);
        private const int concurrentWorkers = 2;
        static void Main(string[] args)
        {
            if (!File.Exists("appsettings.json"))
            {
                Console.Error.WriteLine("appsettings.json was not found!");
                conf = new Config();
                File.WriteAllText("appsettings.json", JsonConvert.SerializeObject(conf, Formatting.Indented));
                return;
            }
            conf = JsonConvert.DeserializeObject<Config>(File.ReadAllText("appsettings.json"));
            Log.call_for_humans_discord_webhook = conf.call_for_humans_discord_webhook;

            httpClient = new HttpClient();
            httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(
                System.Text.Encoding.ASCII.GetBytes($"{conf.webdav_username}:{conf.webdav_password}")));
            //tf = new Telefranz("scheduler", conf.kafka_bootstrap);

            scratch = Scratch.LoadScratch();

            for (var i = 0; i < concurrentWorkers; i++)
            {
                Task.Run(threadwork);
            }
            while (true)
            {
                Task.WaitAll(
                    checkCalendars(),
                    Task.Delay(calendarNaptime)
                    );
            }
        }
        private static async Task checkCalendars()
        {
            try
            {
                lock (scratch)
                {
                    scratch.agenda.Clear();
                }
                Task.WaitAll(
                    checkCalendar(conf.calendar_twitch, "youtube", (ref Schedulable.Schedulable n) =>
                    {
                        n.ScedulableType = Schedulable.ScedulableType.YTRelease;
                    }),
                    checkCalendar(conf.calendar_twitch, "twitch", (ref Schedulable.Schedulable n) =>
                    {
                        n.ScedulableType = Schedulable.ScedulableType.TwitchStream;
                    })
                );
                lock (scratch)
                {
                    scratch.Save();
                }
            }
            catch (Exception e)
            {
                Console.Error.WriteLine(e);
            }
            Console.WriteLine($"calendars pulled, scratch has {scratch.agenda.Count} schedulables.");

            foreach (var s in scratch.agenda)
            {
                if ((s.Showtime - conf.preshowBufferTime) - DateTime.Now <= calendarNaptime)
                {
                    var copy = JsonConvert.DeserializeObject<Schedulable.Schedulable>(JsonConvert.SerializeObject(s));
                    workQueue.Enqueue(copy);
                    _signal.Set();
                }
            }
        }

        private delegate void schedulableCreate(ref Schedulable.Schedulable creating);
        private static async Task checkCalendar(string calendarUri, string calLabel, schedulableCreate createSchedulable)
        {
            //?export is a hack to allow me to access the calendar
            //it likes to throw an error saying "this is the webDAV interface, use webDAV" at my webDAV client, stopping me from using webDAV.
            var calString = await httpClient.GetStringAsync(conf.webdav_uri + calendarUri + "?export");
            var calT = Calendar.Load(calString);
            var knownChecklist = new List<Schedulable.Schedulable>();
            lock (scratch)
            {
                scratch.Calendars[calLabel] = calString;
                foreach (var calOccurrence in calT.GetOccurrences(searchStart, searchEnd))
                {
                    var asEvent = calOccurrence.Source as Ical.Net.CalendarComponents.CalendarEvent;

                    var newSchedulable = new Schedulable.Schedulable()
                    {
                        Event = ser.SerializeToString(asEvent),
                        OccurrenceStart = calOccurrence.Period.StartTime.Date,
                        OccurrenceEnd = calOccurrence.Period.EndTime.Date,
                        Showtime = calOccurrence.Period.StartTime.Date,
                    };
                    createSchedulable(ref newSchedulable);
                    scratch.agenda.Add(newSchedulable);
                }
            }
        }
        private static void threadwork()
        {
            Schedulable.Schedulable todo = null;
            while (true)
            {
                _signal.WaitOne(calendarNaptime);

                if (!workQueue.TryDequeue(out todo)) { continue; }
                
                Console.WriteLine("threadwork consumes!");
                Task.Delay(todo.Showtime - conf.preshowBufferTime - DateTime.Now);
                Console.WriteLine("time to prep!");

                switch (todo.ScedulableType)
                {
                    case Schedulable.ScedulableType.TwitchStream:
                        try
                        {
                            // var handler = new TwitchStreamHandler();
                            // handler.Handle();
                        }
                        catch(Exception e)
                        {
                            Log.Panic($"error in twitch stream handler! Panicking!\n{JsonConvert.SerializeObject(e)}");
                        }
                        break;
                    // case Schedulable.ScedulableType.YTRelease:
                    //     break;
                    default:
                        Log.Panic($"unknown schedulable type! abandoning!");
                        break;
                }
            }
        }
    }
}